The present invention generally relates to the field of multiple alert pagers in which reception of various signal codes results in providing in any one of a plurality of different associated alerts. These alerts are used to advise the user (carrier) of the pager to take appropriate action, such as calling his home or office. The present invention more specifically relates to the field of combined tone only and tone and voice pagers in which a tone only alert, consisting only of one or more audible alert tones, or a tone and voice alert, consisting of an initial audible alert tone followed by audible voice signals, are provided in response to the reception of different predetermined signal codes.
Multiple alert paging devices which provide any of several different alerts in response to the reception of different signal codes are known and one such device which is operative to provide audible alerts in response to received sequential tone codes is illustrated in U.S. Pat. No. 4,181,893 to Edward L. Ehmke and assigned to Motorola, Inc. In this multiple alert paging device the reception of a signal code comprising a tone coded preamble followed by five sequential predetermined code tones will result in providing one distinctive audible alert if a unique sixth tone is present after the five code tones and a different alert if this sixth tone is absent. The paging receiver illustrated in the Ehmke U.S. Patent comprises a tone only pager since the only alerts provided consist of various audible alert tones resulting from audio signals generated by an audio oscillator circuit within the pager. In some tone only pagers a switch allowing for selective premature termination of audible alerts has been provided.
In tone and voice pagers a predetermined signal code followed by voice information is received by the pager and the pager responds by providing an audible alert comprising an initial alert tone followed by an audible response corresponding to the received voice information. Typically, such tone and voice pagers are provided with an audio monitor switch which, when actuated, will result in the pager continuously providing audible signals corresponding to audio frequency signals received by the pager. Generally the audio frequency signals received by the pager comprise audio modulation of a carrier signal and may include audio tones which are part of the signal codes. In some tone and voice pagers the audio monitor switch is also utilized to provide for termination of a tone and voice alert mode wherein actuation/deactuation of the switch results in terminating the audible alert, during tone and/or voice portions of the alert, provided by the pager. In some tone and voice pagers switches have been provided which, when actuated, terminate either the audible alert tone or the subsequent voice message, and in some tone and voice pagers termination of the audible alert tone is prohibited until the occurrence of the voice message.
Combined tone only and tone and voice audible alert pagers are known and one such pager is the BPR 2000 Decimal Digital Radio Pager manufactured by Motorola, Inc. In such a combined pager signal codes received by the pager selectively result in implementing either a tone only or a tone and voice mode of audible alert operation. This is desirable since many times it is only necessary to alert the user (carrier) of the pager to the fact that he is being called (paged) whereas in other instances it is necessary to convey additional voice information to the user.
The operation of such combined tone only and tone and voice pagers has not been entirely satisfactory. In the BPR 2000 pager an audio monitor switch is provided which allows the user, if he desires, to continuously monitor received audio information signals. This switch is also utilized to terminate both the tone only and tone and voice alert modes of operation upon release of the switch. This has resulted in allowing undesired modes of operation since by depressing the audio monitor switch after a tone only alert, the user may hear a subsequent voice message which is intended for a different pager and mistakenly conclude that the voice message was intended for him. In addition, premature actuation and release of the audio monitor switch during the tone and voice mode of operation can result in terminating the tone and voice mode during the occurrence of the initial tone and voice audible alert tone thus resulting in the user being unaware that a tone and voice audible alert rather than a tone only audible alert should have been produced by the pager. In essence, prior combined tone only and tone and voice pagers have been inadequate in providing safeguards so that the user of the pager can properly distinguish between tone only and tone and voice alerts despite the occurrence of actuation/deactuation of a manual switch that is used for audio channel monitoring and/or for terminating the tone only and tone and voice alert modes.